A known cassette consists of an annular housing into which the sample is placed from one board side. The sample is secured in the cassette by means of a retaining spring which is locked in the cassette by a rotary movement through 90.degree..
A disavantage of the csassettes of the prior art is that they are not readily adapted for use in conjunction with automated processes and, more specifically, for use by robots. Indeed, for the fully automatic insertion of a sample of melt into an X-ray spectrometer it is an important prerequisite that the setting up of the sample in the sample cassette be preformed by robots.